Safe cutting heads and systems for fast removal of a target tissue

ABSTRACT

A safe and efficient cutting heads for removing a target tissue from a subject during a surgical procedure are provided, the cutting heads composing a part of systems that address several problems, including clogging of state-of-the-art systems during removal of such tissue, for example. The target tissue can include any tissue that is accessible through a small surgical opening, for example, a joint tissue such as a meniscus or an intervertebral tissue, such as a nucleus pulposus. The devices can be referred to as orthopedic tissue removal devices having cutting heads associated with vacuum systems, making the systems useful in several procedures, including X-LIF (lateral approach to an intervertebral fusions) procedures, T-LIF (transforaminal approach to intervertebral fusions) procedures, P-LIF (posterior approach to intervertebral fusions), and a percutaneous, transforaminal approach (Kambin triangle access).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/566,629, filed Dec. 3, 2011, and U.S. Provisional Application No.61/596,865, filed Feb. 9, 2012, each application of which is herebyincorporated herein by reference in its entirety.

BACKGROUND

1. Field of the Invention

The teachings provided herein are generally directed to a safe andefficient cutting head for removing a target tissue from a subjectduring a surgical procedure.

2. Description of the Related Art

Intervertebral disc disease is a major worldwide health problem. In theUnited States alone almost 700,000 spine procedures are performed eachyear and the total cost of treatment of back pain exceeds $30 billion.Age related changes in the disc include diminished water content in thenucleus and increased collagen content by the 4.sup.th decade of life.Loss of water binding by the nucleus results in more compressive loadingof the annulus. This renders the annulus more susceptible todelamination and damage. Damage to the annulus, in turn, acceleratesdisc degeneration and degeneration of surrounding tissues such as thefacet joints.

The two most common spinal surgical procedures performed are discectomyand spinal fusion. These procedures only address the symptom of lowerback pain, nerve compression, instability and deformity. The objectiveof the spinal disc fusion procedure is to restore, maintain andstabilize disc height, and/or reduce back pain. The procedure isgenerally performed by removing central disc material such and innerannulus, nucleus pulposus and the cartilage on the endplates beforereplacing with bone graft and a scaffold to effect fusion of thevertebral bodies within the treated disc for height stabilization. Thisremoval process is called a discectomy and is both tedious andfrequently inadequate which can result in compromised fusion, as well astraumatic and time consuming due to the large incision and dissectionsrequired to expose the disc for discectomy.

In a typical discectomy procedure, a nucleotomy is first performed inwhich the nucleus is loosened by using a curette or a manual shaver toshear the nucleus loose and then removed using a rigid grasper called arongeur. The surgeon has to insert the rongeur through an opening in thedisc called an anulotomy, grasp nucleus and remove out of the disc andthe surgical access, clean the jaws and reinsert for more grasping ofdisc repeatedly. This process can pose safety issues for tissues inbetween tool passage such as nerves. Furthermore, disc debris leftbehind can hinder efficient subsequent tissue removal and insertion ofthe discectomy tools into the disc. The second step is decortication inwhich cartilage attached to the bone (cartilaginous endplate) is removedby the use of rigid scrapers such as a curette or a rasp to help promotea strong intervertebral fusion. Peeled cartilage are removed by scoopingwith a curette and withdrawn out of the body by the use of a rongeur.Tissue debris left behind can also compromise efficiency andeffectiveness of the decortication resulting in a weaker fusion.Moreover, corners inside the discs are often hard to reach by currentstate-of-the art tools, often leaving additional areas of inadequatedisc removal.

In addition, state-of-the-art systems using a combination of suction andcutting suffer clogging problems due to excised tissue becoming lodgedin the system. One of skill will appreciate that problems with cloggingduring a surgical procedure can be problematic, and a solution to suchclogging problems is highly desired.

Although several advanced tools have been developed, none have addressedall of these issues adequately. One of skill in the art would certainlyappreciate a discectomy system that is (i) less tedious and timeconsuming to use, (ii) less prone to clogging by excised tissue; (iii)safer to the subject undergoing the surgery, and (iv) more effective inpromoting a strong intervertebral fusion.

SUMMARY

The teachings provided herein are generally directed to a safe andefficient cutting head for removing a target tissue from a subjectduring a surgical procedure. The target tissue can include any tissuethat is accessible through a small surgical opening, for example, ajoint tissue such as a meniscus, in some embodiments, or anintervertebral tissue, such as a nucleus pulposus, in other embodiments.

The cutting head can be tubular with a cutting surface forming at leasta first plane on a distal perimeter of cutting head, the cutting head inoperable communication with a suction device to excise a target tissuein a manner that facilitates an ease of removal of the tissue with thesuction. The cutting surface can be flat, sinusoidal, or serrated, forexample, and the first plane of the cutting surface may be at an angle,θ_(FP), that deviates up to 75° from a position that is orthogonal tothe central axis of the cutting head. In some embodiments, the cuttingsurface can have a second plane may be at an angle, θ_(SP), thatdeviates up to 75° from a position that is orthogonal to the centralaxis of the cutting head. In some embodiments, the cutting head has acutting blade and a blade guard for guarding a perimeter tissue from thecutting blade.

As such, the teachings include a tubular cutting head for removing atarget tissue of a subject. In these embodiments, the cutting head canhave an outer perimeter that circumscribes a lumen through the cuttinghead, the lumen having a central axis. The cutting head can also have aforward cutting blade on a distal edge of the outer perimeter, theforward cutting blade configured for (i) cutting a target tissue in aforward stroke of the cutting head and (ii) directing the cut tissueinto the lumen. And, the cutting head can also have a blade guardpositioned distal to the forward cutting blade and configured to guard aperimeter tissue from the forward cutting blade upon the forward strokethe blade guard having a width that is smaller than the width of atransverse cross-section of the lumen to facilitate entry of the targettissue into the lumen on the forward stroke.

In some embodiments, the cutting head can have a backward cutting bladefor cutting the target tissue in a backward stroke of the cutting head,a transverse cutting blade for cutting the target tissue in a transversestroke of the cutting head, or a combination thereof. In someembodiments, a transverse cutting blade can be positioned on the bladeguard for cutting the target tissue in a transverse stroke of thecutting head.

In some embodiments, the backward cutting blade can be positioned on thedistal edge of the outer perimeter for cutting the target tissue in thebackward stroke of the cutting head. In some embodiments, the backwardcutting blade can be positioned on the blade guard for cutting thetarget tissue in the backward stroke of the cutting head, the bladeguard having a double-edged blade tip point back into the lumen at anangle, θ₂, of greater than 90° to trap and/or cut tissue in the lumen inthe backwards stroke of the cutting head.

Since the cutting head can be designed to remove tissue through use of asuction, the teachings are also directed to systems of a cutting headthat operably connect the cutting head with a suction assembly. As such,the teachings include a such a surgical, tissue removal system thatincludes a tubular cutting head for removing a target tissue of asubject. The system can include a cutting head having an outer perimeterthat circumscribes a flow of suction through the cutting head; a lumencircumscribed by the outer perimeter, the lumen guiding the flow ofsuction and having a central axis; a forward cutting blade on a distaledge of the outer perimeter, the forward cutting blade configured for(i) cutting the target tissue in a forward stroke of the cutting headand (ii) directing the cut tissue into the lumen; and, a blade guardpositioned distal to the forward cutting blade and configured to guard aperimeter tissue from the forward cutting blade upon the forward strokethe blade guard. In some embodiments, the blade guard can have a widththat is smaller than the width of a transverse cross-section of lumen tofacilitate entry of the target tissue into the lumen on the forwardstroke.

The cutting head can be configured for an operable communication betweenthe lumen and a source of a suction, such that the systems include asuction assembly in operable communication with the cutting head forcreating the flow of suction for removing the target tissue through thelumen and out of the subject, the suction assembly comprising a rigidsuction tube with a central axis. In some embodiments, the operablecommunication includes the use of one or more suction ports positionedjust proximal to the most proximal point of the distal edge of the outperimeter of the cutting head. In some embodiments, the one or moreports can be located from about 3 mm to about 20 mm proximal to the mostproximal point of the distal edge.

In some embodiments, the suction assembly comprises an at leastsubstantially rigid suction tube having a proximal end and a distal end,the distal end in the operable communication with the cutting head, andthe distal end configured for communicating with a source of suction forthe suction assembly. In some embodiments, the at least substantiallyrigid suction tube can be formed as a single unit with the cutting head.

In some embodiments, the central axis of the lumen is at an angle, θ₁,ranging from about 5° to about 90° from the central axis of the rigidsuction tube, and the forward cutting blade is located about 3 mm toabout 25 mm from the vertex of the angle, θ₁.

The system of claim 10, the central axis of the lumen has a point ofexit at the forward cutting blade, and the point of exit is located at atransverse distance of about 3 mm to about 25 mm that is orthogonal tothe central axis of the rigid suction tube.

In some embodiments, the central axis of the lumen can be at an angle,θ₁, ranging from about 5° to about 90° from a central axis of the flowof suction at the distal end of the suction assembly, and the forwardcutting blade can be located about 3 mm to about 25 mm from the vertexof the angle, θ₁. In some embodiments, the operable communicationbetween the cutting head and the suction assembly can be articulating,and the angle can be adjustable. In some embodiments, the operablecommunication between the cutting head and the suction assembly can berigid, and the angle can be fixed.

In some embodiments, the central axis of the lumen is at an angle, θ₁,ranging from 1° to 180° from a central axis of the flow of suction atthe distal end of the suction assembly, and the forward cutting blade islocated 3 mm to 25 mm from the vertex of the angle, θ₁. In theseembodiments, additional angle, θ₃, is located 5 mm to 25 mm proximal toθ₁, and angles θ₁ and θ₃ are independently selected to range from about0° to about 180°, with the limitation that (i) the net angle, θ₄,between the central axis of the lumen of the cutting head and thecentral axis of a rigid suction tube located proximal to θ₃ ranges from0° to 90°; and, (ii) the distance between the central axis of the lumenof the cutting head and the central axis of the rigid suction tuberanges from 2 mm to 30 mm.

It should be appreciated that the cutting heads and systems taughtherein have a variety of applications known to one of skill. In someembodiments, the target tissue can be a nucleus pulposus, and theperimeter tissue can be an annulus fibrosis, for example.

As such, the teachings are also directed to a surgical, tissue removalsystem for a discectomy, and the systems can comprise a tubular cuttinghead for removing a nucleus pulposus from a subject. In theseembodiments, the systems can include a cutting head having an outerperimeter that circumscribes a flow of suction through the cutting head;a lumen circumscribed by the outer perimeter, the lumen guiding the flowof suction; a forward cutting blade on a distal edge of the outerperimeter, the forward cutting blade configured for (i) cutting thenucleus pulposus in a forward stroke of the cutting head and (ii)directing the cut nucleus pulposus into the lumen; a backward cuttingblade for cutting the nucleus pulposus in a backward stroke of thecutting head; a transverse cutting blade for cutting the nucleuspulposus in a transverse stroke of the cutting head; and, a blade guardpositioned distal to the forward cutting blade and configured to guardan annulus fibrosis tissue from the forward cutting blade upon theforward stroke. And, the blade guard can have a width, for example, thatis smaller than the width of a transverse cross-section of the lumen tofacilitate entry of the target tissue into the lumen on the forwardstroke.

The teachings also include a method of removing a target tissue from asubject. In these embodiments, the method can comprise creating anopening in a subject for access to a target tissue; inserting a cuttinghead taught herein through the opening to access the target tissue inthe subject; and, forcing the cutting head in a forward direction on asurface comprising the target tissue to remove the target tissue. Theforward direction can include a force vector that moves (i) at leastsubstantially on a plane containing the central axis of the lumen of thecutting head, (ii) at least substantially on the surface comprising thetarget tissue, and (iii) toward the perimeter tissue that is protectedby the blade guard. And, the method can include capturing the targettissue in the lumen of the cutting head, as well as removing the targettissue through the lumen and out of the subject.

In some embodiments, the method comprises forcing a cutting head taughtherein in a backward direction on a surface comprising the target tissueto remove the target tissue. The backward direction can include a forcevector that moves (i) at least substantially on a plane containing thecentral axis of the lumen of the cutting head, (ii) at leastsubstantially on the surface comprising the target tissue, and (iii)away from the perimeter tissue that is protected by the blade guard.

In some embodiments, the method comprises forcing a cutting head taughtherein in a transverse direction on a surface comprising the targettissue to remove the target tissue. The transverse direction can includea force vector that moves (i) at an angle ranging from about 15° toabout 150° from a plane containing the central axis of the lumen of thecutting head, (ii) at least substantially on the surface comprising thetarget tissue, and (iii) in contact with the perimeter tissue that isprotected by the blade guard.

The teachings are also directed to an obturator, guard cannula toprotect a subject during entry and exit of an elongated surgical cuttingdevice having a non-linearity. In these embodiments, the guard cannulacan comprise an entry hub having an inner perimeter, an outer perimeter,and an irrigation port that communicates between the inner perimeterwith the outer perimeter; and, a linear, elongated split-tube having aproximal end, a distal end, and a lumen. In these embodiments, theproximal end of the split-tube can (i) circumscribe at least a portionof the inner perimeter of the hub and (ii) be in operable communicationwith the irrigation port. In these embodiments, the communication can beoperable to receive an irrigation fluid from the irrigation port, thetransport of the irrigation fluid to a target tissue including, forexample, a movement of the irrigation fluid from the irrigation port tothe distal end of the split-tube on a luminal surface of the split-tube.

The distal end of the split-tube can also have any configuration desiredby one of skill. For example, the distal end can at least substantiallypointed and/or sharp. In some embodiments, the distal end can be atleast substantially blunt to avoid damage to an entry tissue uponcontact of the distal end with the entry tissue. The split-tube can alsohave a length ranging from about 10 cm to about 60 cm and a widthranging from about 5 mm to about 16 mm. Moreover, the split in thesplit-tube can compose a gap having a width ranging from about 4 mm toabout 14 mm, the split accommodating a non-linearity in the surgicaldevice.

As described above, the systems taught herein can be used in a varietyof procedures for removal of a target tissue from a subject including,for example, removal of a meniscus or a discectomy. In some embodiments,the surgical cutting device used with the guard cannula can be adiscectomy device. And, in some embodiments, the entry tissue includesthe subject's epithelial tissue, muscle tissue, nerve tissue, connectivetissue, a blood vessel, bone, cartilage, or a combination thereof,leading to the nucleus pulposus. As such, the target tissue can includethe nucleus pulposus in some embodiments.

The teachings are also directed to a surgical tissue removal kit havinga surgical tissue removal system and a guard cannula, using anycombination of system and cannula embodiments taught herein. In someembodiments, the kits can be a discectomy kit. As such, in someembodiments, the entry tissue includes the subject's epithelial tissue,muscle tissue, nerve tissue, connective tissue, a blood vessel, bone,cartilage, or a combination thereof, leading to the nucleus pulposus. Assuch, the target tissue can include the nucleus pulposus in someembodiments.

The teachings are also directed to a method of using the kits to removea target tissue. In some embodiments, the method comprises creating anopening in a subject for access to a target tissue; inserting thecutting head of the kit through the entry hub and the elongatedsplit-tube of the guard cannula of the kit; inserting the cutting headof the kit through the opening to access the target tissue in thesubject while protecting the entry tissue with the blunt, distal end ofthe split-tube. Otherwise, methods of using the tissue removal systemsare the same or similar to those taught herein. One of skill willappreciate having such kits for discectomies, for example, in which thetarget tissue can be a nucleus pulposus, and the perimeter tissue can bean annulus fibrosis. One of skill will also appreciate having a kit witha guard cannula that helps protect the subject's epithelial tissue,muscle tissue, nerve tissue, connective tissue, a blood vessel, bone,cartilage, or a combination thereof, leading to the nucleus pulposus insuch procedures.

One of skill will appreciate that the embodiments taught herein areprovided for purposes of outlining general concepts, and that severaladditional embodiments are included in, and can be derived from, theteachings provided herein.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-1D illustrates a variety of tubular cutting head configurationsthat can be fabricated from stock tube, according to some embodiments.

FIGS. 2A-2E show blade configurations, according to some embodiments.

FIGS. 3A-3C show cross section of individual blade profiles, accordingto some embodiments.

FIGS. 4A-4C illustrate a cutting head, according to some embodiments.

FIGS. 5A and 5B illustrate the angulation of a cutting head 500,according to some embodiments.

FIG. 6 illustrates an obturator, guard cannula, according to someembodiments.

FIG. 7 illustrates a surgical tissue removal kit, according to someembodiments.

FIGS. 8A-8C illustrate a system or kit that can irrigate concurrent withapplication of suction, and without the obturator, guard cannula inplace, according to some embodiments.

FIGS. 9A-9H show cutting head designs that were tested, according tosome embodiments.

FIGS. 10A-10E illustrate the advancements in the cutting head, accordingto some embodiments.

FIGS. 11A-11C illustrate a bayonet-type communication between a cuttinghead and a suction assembly, according to some embodiments.

DETAILED DESCRIPTION OF THE INVENTION

The teachings provided herein are generally directed to a safe andefficient cutting head for removing a target tissue from a subjectduring a surgical procedure. The target tissue can include any tissuethat is accessible through a small surgical opening, for example, ajoint tissue such as a meniscus or an intervertebral tissue, such as anucleus pulposus. In some embodiments, the devices taught herein can bereferred to as an orthopedic tissue removal device. In some embodiments,the devices taught herein are useful in X-LIF (lateral approach to anintervertebral fusions) procedures, T-LIF (transforaminal approach tointervertebral fusions) procedures, P-LIF (posterior approach tointervertebral fusions), or a percutaneous, transforaminal approach(Kambin triangle access).

The term “subject” and “patient” can be used interchangeably in someembodiments and refer to an animal such as a mammal including, but notlimited to, non-primates such as, for example, a cow, pig, horse, cat,dog, rat and mouse; and primates such as, for example, a monkey or ahuman. As such, the terms “subject” and “patient” can also be applied tonon-human biologic applications including, but not limited to,veterinary, companion animals, commercial livestock, and the like.

The cutting head can be tubular with a cutting surface forming at leasta first plane on a distal perimeter of cutting head, the cutting head inoperable communication with a suction device to excise a target tissuein a manner that facilitates an ease of removal of the tissue with thesuction.

The cutting surface can be flat, sinusoidal, or serrated, for example,and the first plane of the cutting surface may be at an angle, θ_(FP),that deviates up to 75° from a position that is orthogonal to thecentral axis of the cutting head. In some embodiments, the cuttingsurface can have a second plane may be at an angle, θ_(SP), thatdeviates up to 75° from a position that is orthogonal to the centralaxis of the cutting head. In some embodiments, the cutting head has acutting blade and a blade guard for guarding a perimeter tissue from thecutting blade. In some embodiments, θ_(FP) and θ_(SP) can beindependently selected to range from 0° to about 75°, from about 5° toabout 75°, from about 10° to about 70°, from about 15° to about 65°,from about 10° to about 60°, from about 5° to about 55°, from about 15°to about 50°, from about 20° to about 45°, from about 15° to about 40°,from about 25° to about 35°, or any angle or range of angles therein inincrements of 1°.

FIGS. 1A-1D illustrates a variety of tubular cutting head configurationsthat can be fabricated from stock tube, according to some embodiments.FIG. 1A shows a cutting head stock tube 100 having a first plane 105 atan angle, θ_(FP), that is orthogonal to the central axis 110 of thelumen of the stock tube 100. FIG. 1B shows a cutting head stock tube 100having a first plane 105 at an acute angle, θ_(FP), to the central axis110 of the lumen of the stock tube 100, the acute angle ranging from 1°to about 75°. FIG. 1C shows a cutting head stock tube 100 having a firstplane 105 at an acute angle, θ_(FP), to the central axis 110 of thelumen of the stock tube 100, the acute angle, θ_(FP), ranging from 1° toabout 75°; and, having a second plane 105 at an angle, θ_(SP), that isorthogonal to the central axis 110 of the lumen of the stock tube 100.FIG. 1D shows a cutting head stock tube 100 having a first plane 105 atan acute angle, θ_(FP), to the central axis 110 of the lumen of thestock tube 100, the acute angle ranging from 1° to about 75°; and,having a second plane 105 at an angle, θ_(SP), to the central axis 110of the lumen of the stock tube 100, the acute angle, θ_(SP), rangingfrom 1° to about 75°.

The cutting head can be fabricated from any material known to one ofskill to be suitable in a surgical environment for the uses taughtherein. For example, a hard material with hardness greater than RockwellC 30 or greater than Rockwell C 45 can be suitable in some embodiments.In some embodiments, the cutting head can be comprised of a componentselected from the group consisting of tempered steel, stainless steel,high carbon steel, titanium or titanium alloy, ceramic, diamond andobsidian. In some embodiments, the stainless steel can comprise 304stainless steel, 316 stainless steel, 17-4 PH stainless steel, 400series stainless steel, or any other stainless steels known to one ofskill to be suitable for the cutting functions taught herein. In someembodiments, the cutting head can be made of cobalt chromium, tungstencarbide, or a ceramic.

The tube forming the cutting head can have a wall thickness, forexample, from 0.003″ to 0.020″ or more specifically 0.005″ to 0.012″.The cross-sectional area of the cutting head can range from 0.120inches² to 1.5 inches² or, in some embodiments, from 0.180 in² to 0.400in². The width in any direction can range from 0.080″ to 0.400″ or moreand, in some embodiments, 0.160″ to 0.250″. In some embodiments, thecutting head can have a maximum transverse cross section dimensionranging from about 3.0 mm to about 20.0 mm, from about 4.0 mm to about15.0 mm, from about 4.0 mm to about 12.0 mm, from about 5.0 mm to about10.0 mm, about 5.0 mm to about 8.0 mm, or any range therein inincrements of 0.1 mm. In some embodiments, the cutting heads havediameters of about 4.8 mm, about 5.0 mm, about 5.2 mm, about 5.4 mm,about 5.8 mm, about 6.0 mm, about 6.2 mm, about 6.4 mm, about 6.6 mm,about 6.8 mm, about 7.0 mm, about 7.2 mm, about 7.4 mm, about 7.6 mm,about 7.8 mm, about 8.0 mm, about 8.2 mm, and any 0.1 mm incrementtherein.

The distal perimeter of a cutting head can be on the first plane or thesecond plane, or a combination thereof, and the cutting surfaces can beany cutting surface known to one of skill, such as a razor surface, aserrated surface, or a sinusoidal surface, in some embodiments. Thereare a variety of possible blade configurations known to one of skill inthe art of cutting blade design, and any such configuration may be used.For example, the cutting surface can have teeth and gullets between theteeth. The spacing between the teeth can be equal or variable, and thedepth of the gullets can be equal or variable, and any combination ofteeth and gullets can be used. In some embodiments, the direction of theprotrusion of the teeth can be offset from the direction of theremainder of the walls of the cutting head. In some embodiments, theteeth are in the same direction as the remainder of the walls of thecutting head, such that the teeth are merely an extension of the wallsof the cutting head, with no shift in direction toward the lumen of thecutting head or away from the lumen of the cutting head. In someembodiments, there is a pattern of directional shift of the teeth awayfrom, or toward, the lumen of the cutting head. For example, the patterncan be a sequence of toward, away, toward, away, no shift, and thesequence is repeated around the distal edge of the outer perimeter ofthe cutting head. In some embodiments, all teeth can point toward thelumen, and in some embodiments, all teeth can point away from the lumen.In some embodiments, the teeth alternate toward the lumen and away fromthe lumen tooth-by-tooth. And, in some embodiments, the teeth aregradually toward and away from the lumen at gradually increases anddecreasing angles, tooth-by-tooth, to create an appearance of waves asthe teeth circle the distal edge of the outer perimeter. The sequencecan also be entirely random.

FIGS. 2A-2E show blade configurations, according to some embodiments.FIG. 2A shows a 5 tooth shift pattern of toward, away, toward, away, noshift, repeat. FIG. 2B shows a random shift pattern. FIG. 2C shows awavy shift pattern. FIG. 3D shows a 3 tooth shift pattern of away,toward, no shift, repeat. And, FIG. 3E shows a simple away, toward,repeat shift pattern.

The choice of blade configuration can be combined with a choice of bladeprofile, in some embodiments. Those of skill in the art of designingcutting blades will appreciate that the cutting heads taught herein canhave a variety cutting actions, such as a chisel action, sawing action,slicing action, and ripping action, for example. As such, the bladeprofile chosen can be varied to use any blade profile known to one ofskill. In some embodiments, the teeth are beveled. In some embodiments,the cutting heads have teeth that point backward as well as forward toinclude forward cutting surfaces in addition to backward cutting“spurs.”

As such, the teachings include a tubular cutting head for removing atarget tissue of a subject. And, the tube can be an elongated, tubularstructure of any shape, such as circular tube, a square tube, arectangular tube, an elliptical tube, a pentagonal tube, a hexagonaltube, heptagonal, an octagonal tube, and the like, such that any numberof sides, curvatures, or combinations thereof can be used in someembodiments. In some embodiments, a circular tube is used.

The cutting heads can have a combination of blade types, for example,forward-cutting blades, backward-cutting blades, and transverse cuttingblades, as well as protrusions, hooks, and the like, for grabbing,ripping, or otherwise removing tissue. In some embodiments, the cuttinghead can have a backward cutting blade for cutting the target tissue ina backward stroke of the cutting head, a transverse cutting blade forcutting the target tissue in a transverse stroke of the cutting head, ora combination thereof. In some embodiments, a transverse cutting bladecan be positioned on the blade guard for cutting the target tissue in atransverse stroke of the cutting head.

FIGS. 3A-3C show cross section of individual blade profiles, accordingto some embodiments. FIG. 3A shows a planar-concave blade profile. FIG.3B shows a wedge blade profile. And, FIG. 3C shows a chisel bladeprofile. Likewise, it should be appreciated that the blades can bedesigned to have any configuration, including a single-edge,double-edge, single barb, double-barb, straight tip, barbed tip, and thelike, to assist with any form of tissue removal, including cutting,slicing, chiseling, scraping, gouging, sawing, grinding, and ripping ofa tissue for efficiency in removal during a surgery, for example.

FIGS. 4A-4C illustrate a cutting head, according to some embodiments.FIG. 4A shows an oblique view of the cutting head, and FIG. 4B shows alateral view. The cutting head 400 can have an outer perimeter 405 thatcircumscribes a lumen 410 through the cutting head 400, the lumen 410having a central axis 415. The cutting head 400 can also have a forwardcutting blade 420 on a distal edge 425 of the outer perimeter 405, theforward cutting blade 420 configured for (i) cutting a target tissue(not shown) in a forward stroke of the cutting head 400 and (ii)directing the cut tissue into the lumen 410. And, the cutting head 400can also have a blade guard 430 positioned distal to the forward cuttingblade 420 and configured to guard a perimeter tissue (not shown) fromthe forward cutting blade 420 upon the forward stroke the blade guard430 having a width 433 that is smaller than the width 422 of atransverse cross-section of the lumen 410 to facilitate entry of thetarget tissue into the lumen 410 on the forward stroke. And, as shown inFIGS. 4A-4C, the lateral surfaces 409 of the blade guard can also beserrated, or otherwise sharp cutting surfaces, for transverse cutting.

Since the cutting head can be designed to remove tissue through use of asuction 444, the teachings are also directed to systems of a cuttinghead that operably connect the cutting head with a suction assembly 484(distal end only shown). As such, FIG. 4C also shows such a surgical,tissue removal system that includes a tubular cutting head 400 forremoving a target tissue (not shown) of a subject. The system caninclude a cutting head 400 having an outer perimeter that circumscribesa flow of suction 444 through the cutting head 400; a lumen 415circumscribed by the outer perimeter 405, the lumen 410 guiding the flowof suction 444 and having a central axis 415; a forward cutting blade420 on a distal edge 425 of the outer perimeter 405, the forward cuttingblade 420 configured for (i) cutting the target tissue in a forwardstroke of the cutting head 400 and (ii) directing the cut tissue intothe lumen 410; and, a blade guard 430 positioned distal to the forwardcutting blade 420 and configured to guard a perimeter tissue (not shown)from the forward cutting blade 420 upon the forward stroke the bladeguard 430.

The cutting head can be configured for an operable communication betweenthe lumen 410 and a source of the suction 444, such that the systems 400include the suction assembly 484 in operable communication with thecutting head 400 for creating the flow of suction 444 for removing thetarget tissue through the lumen 410 and out of the subject, the suctionassembly 484 comprising a rigid suction tube 488 with a central axis. Insome embodiments, the operable communication includes the use of one ormore suction ports 466 positioned just proximal to the most proximalpoint of the distal edge of the out perimeter of the cutting head. Insome embodiments, the one or more suction ports 466 can be located fromabout 3 mm to about 20 mm proximal to the most proximal point of thedistal edge 425. While not intended to be bound by any theory ormechanism of action, one of skill will appreciate that a source ofadditional air can be useful when suctioning within a region that cancreate vacuum which would otherwise impede or cease the flow of suctionthat transports excised tissue away from the surgical space during theremoval of the tissue. The suction ports 466 can be used to provide theadditional air to avoid creating of the vacuum in the surgical space.

Any suction assembly construction known to one of skill can be used inmany embodiments. In some embodiments, the suction assembly 484comprises an at least substantially rigid suction tube 488 having aproximal end (not shown) and a distal end 499, the distal end 499 in theoperable communication with the cutting head 400, and the distal end 499configured for communicating with a source of suction 444 for thesuction assembly 484. In some embodiments, the at least substantiallyrigid suction tube 488 can be formed as a single unit with the cuttinghead 400. The phrase, “at least substantially rigid” can refer acomponent that is rigid, or sufficiently rigid such that the desiredfunction is obtained, under the forces that are created with normal use.For example, a desired function may be to prevent or inhibit theoccurrence of a bending moment of the rigid component at one or morepoints along the length of a rigid suction tube upon use of the cuttinghead in the subject.

The following table describes the dimensional ratios of the cutting head400 that were found to facilitate fast-and-efficient tissue removal in adiscectomy. The “Label” is used to show the components and measures thatform the ratios in a small device and a large device.

Label 404 402 Pincer Cutter 403 Width at 401 Diam- Pincer the peakID-Pincer eter Height of the Tip gap 403/ 404/ 401/ (in) (in) arch (in)(in) 402 402 402 Small 0.203 0.098 0.080 0.085 0.483 0.394 0.419 DeviceLarge 0.250 0.140 0.125 0.104 0.560 0.500 0.416 Device Mean--> 0.5210.447 0.417 Theo- 0.7 0.7 0.6 retical Upper Limit Theo- 0.3 0.3 0.3retical Lower Limit

The rigid suction tube can comprise any material known to one of skillto be suitable for the uses taught herein. For example, the rigidsuction tube can comprise any surgical steel, plastic or resinconsidered desirable to one of skill for the devices taught herein. Insome embodiments, the rigid suction tube can comprise the same orsimilar materials as the cutting head. In some embodiments, the rigidsuction tube can comprise a stainless steel, polyetheretherketone(PEEK), polyimide, or carbon fiber. The wall thickness of the shaft canbe any thickness at which a select material will have the physicalproperties desired. In some embodiments, the wall thickness can range,for example, from 0.003″ to 0.020,″ and from 0.005″ to 0.010″ in someembodiments. The luminal surface of the tube can be coated with TEFLON,a hydrophobic coating such as parylene, or a hydrophilic coating such aspolyvinyl alcohol or polyethylene glycol.

In some embodiments, the rigid suction tube can comprise a polymer tubereinforced with a metal braid, a coiled tube, or a tube with transverseslots to facilitate articulation, should articulation be desired in someembodiments. In such embodiments, the cutting head can be angledrelative to the axis of the rigid suction tube by, for example, pullingon a tendon attached to the cutting head on one side, the tendonrunning-along a guide on the side of the rigid suction tube.

FIGS. 5A and 5B illustrate the angulation of a cutting head 500,according to some embodiments. FIG. 5A shows that the central axis 515of the lumen 510 can be at an angle, θ₁, ranging from about 5° to about90° from a central axis 555 of the flow of suction 544 at the distal end599 of the suction assembly (partially shown) 584, and the forwardcutting blade 520 can be located about 2 mm to about 25 mm from thevertex of the angle, θ₁. In some embodiments, θ₁ can range from about 2mm to about 30 mm, from about 2 mm to about 30 mm, from about 2.5 mm toabout 25 mm, from about 3 mm to about 25 mm, from about 4 mm to about 20mm, from about 5 mm to about 15 mm, from about 3 mm to about 25 mm, fromabout 7 mm to about 12 mm, from about 8 mm to about 10 mm, or any rangetherein in increments of 0.5 mm.

In some embodiments, the central axis of the lumen is at an angle, θ₁,ranging from about 5° to about 90° from the central axis of the rigidsuction tube, and the forward cutting blade is located about 3 mm toabout 25 mm from the vertex of the angle, θ₁. And, in some embodiments,the central axis of the lumen has a point of exit at the forward cuttingblade, and the point of exit is located at a transverse distance ofabout 3 mm to about 25 mm that is orthogonal to the central axis of therigid suction tube

In some embodiments, the central axis of the lumen is at an angle, θ₁,ranging from 1° to 180° from a central axis of the flow of suction atthe distal end of the suction assembly, and the forward cutting blade islocated 3 mm to 25 mm from the vertex of the angle, θ₁. In theseembodiments, additional angle, θ₃, is located 5 mm to 25 mm proximal toθ₁, and angles θ₁ and θ₃ are independently selected to range from about0° to about 180°, with the limitation that (i) the net angle, θ₄,between the central axis of the lumen of the cutting head and thecentral axis of a rigid suction tube located proximal to θ₃ ranges from0° to 90°; and, (ii) the distance between the central axis of the lumenof the cutting head and the central axis of the rigid suction tuberanges from 2 mm to 30 mm. As such, the distance in the flow of suctionbetween angles θ₁ and θ₃ can range from about 5 mm to about 30 mm, fromabout 5 mm to about 25 mm, from about 5 mm to about 20 mm, from about 6mm to about 18 mm, from about 7 mm to about 15 mm, or any range ordistance therein in increments of 1 mm.

In some embodiments, the operable communication between the cutting head500 and the suction assembly 584 can be articulating, and the angle, θ₁,can be adjustable. In some embodiments, the operable communicationbetween the cutting head 500 and the suction assembly 584 can be rigid,and the angle, θ₁, can be fixed. In some embodiments, the angle, θ₁, canrange from 0° to about 45°, from about 1° to about 40°, from about 5° toabout 35°, from 10° to about 35°, from 15° to about 40°, from 20° toabout 30°, or any range therein in increments of 1°. In someembodiments, the angle, θ₁, can be about 3°, about 5°, about 10°, about15°, about 20°, about 25°, about 30°, about 35°, about 40°, about 45°,or any angle therein in increments of 1°.

In some embodiments, the backward cutting blade can be positioned on thedistal edge 525 of the outer perimeter 505 for cutting the target tissuein the backward stroke of the cutting head 500. In some embodiments, thebackward cutting blade 531 can be positioned on the blade guard 530 forcutting the target tissue in the backward stroke of the cutting head500. FIG. 5B shows that the blade guard 530 can have a double-edgedblade tip as the backward cutting blade 531 point back into the lumen515 at an angle, θ₂, of greater than 90° from the central axis 515 ofthe lumen 500 to trap and/or cut tissue in the lumen 510 in thebackwards stroke of the cutting head 500. The backward cutting blade 531can be referred to as a “talon” in some embodiments, or “pincer”, as itcan function to grab, shear, and hook tissue for removal.

It should be appreciated that the cutting heads and systems taughtherein have a variety of applications known to one of skill. In someembodiments, the target tissue can be a nucleus pulposus, and theperimeter tissue can be an annulus fibrosis, for example.

A surgical, tissue removal system for a discectomy is provided, and thesystems can comprise a tubular cutting head for removing a nucleuspulposus from a subject. In these embodiments, the systems can include acutting head having an outer perimeter that circumscribes a flow ofsuction through the cutting head; a lumen circumscribed by the outerperimeter, the lumen guiding the flow of suction; a forward cuttingblade on a distal edge of the outer perimeter, the forward cutting bladeconfigured for (i) cutting the nucleus pulposus in a forward stroke ofthe cutting head and (ii) directing the cut nucleus pulposus into thelumen; a backward cutting blade for cutting the nucleus pulposus in abackward stroke of the cutting head; a transverse cutting blade forcutting the nucleus pulposus in a transverse stroke of the cutting head;and, a blade guard positioned distal to the forward cutting blade andconfigured to guard an annulus fibrosis tissue from the forward cuttingblade upon the forward stroke.

Another valuable feature is that the devices taught herein can operatewithout substantial clogging from the flow of excised tissue from thecutting head, and this was accomplished by design. Without intending tobe bound by any theory or mechanism of action, it was discovered thatthe area of a transverse cross-section of the distal end of the cuttinghead should be at least substantially equal to, or less than, thetransverse cross-sectional area of any point that is positioned proximalto the distal end of the cutting head leading to collection of the flowof excised tissue from the cutting head. Such points would include, forexample, any such point of cross-section along the rigid suction tube,or any other component of the section assembly leading to the point ofcollection of the excised tissue, for example, the most proximal orificeat which the pressure difference dumps the excised tissue into acollection canister in some embodiments. The term “at leastsubstantially equal to” means that there may be a smaller transversecross-sectional area, as long as it is limited in magnitude, in someembodiments. In some embodiments, the transverse cross-sectional areacan be at least substantially equal to the transverse cross-sectionalarea of the cutting head if it is no more than 20% less in transversecross-sectional area at the proximally located cross-section. In someembodiments, the transverse cross-sectional area can be at leastsubstantially equal to the transverse cross-sectional area of thecutting head if it is no more than about 3%, about 5%, about 7%, about9%, about 11%, about 13%, about 15%, about 17%, about 19%, about 21%.Any percent therein in increments of 1%, less in transversecross-sectional area at the proximally located cross-section.

The teachings also include a method of removing a target tissue from asubject. In these embodiments, the method can comprise creating anopening in a subject for access to a target tissue; inserting a cuttinghead taught herein through the opening to access the target tissue inthe subject; imaging the depth of the tip of the cutting head using asuitable imaging technique, such as fluoroscopy; and, forcing thecutting head in a forward direction on a surface comprising the targettissue to remove the target tissue while vacuum is activated to suck cuttissue proximally. The forward direction can include a force vector thatmoves (i) at least substantially on a plane containing the central axisof the lumen of the cutting head, (ii) at least substantially on thesurface comprising the target tissue, and (iii) toward the perimetertissue that is protected by the blade guard. And, the method can includecapturing the target tissue in the lumen of the cutting head, as well asremoving the target tissue through the lumen and out of the subject.

The phrase, “at least substantially on . . . ,” can refer to a positionor movement that is sufficient close to the exact desired position suchthat the desired function is obtained, under the forces and conditionsthat are created with normal use of the systems and devices taughtherein. For example, “at least substantially on a plane containing thecentral axis of the lumen of the cutting head” or at least substantiallyon the surface comprising the target tissue” can refer to a position ormovement that is parallel or substantially parallel to the plane orsurface but perhaps off by about 1 um to about 15 mm from the actualplane, or perhaps off by about 0.1° to about 20° in direction ofmovement. The measure of “at least substantially” is used to approximatesituations in which the exact measure or position is not obtained, butfunction desired by a person of ordinary skill is obtained. For example,a reduction of outcome when compared to the best possible outcome can beused to determine what is “at least substantially” the desired outcome.In some embodiments, the desired outcome is at least substantiallyobtained where the best possible outcome is reduced by less than 10%,less than 15%, less than 20%, less than 30%, less than 40% or less than50%. In some embodiments, the desired outcome is at least substantiallyobtained where the best possible outcome is reduced by an amount ofabout 5% to about 30%, about 7% to about 35%, about 10% to about 25%, orany range therein in increments of 1%.

In a discectomy, the opening in the subject can vary, depending on thedisk height of the subject, which is often in the range of about 5 mm-7mm. In some embodiments, the opening in the subject can range in sizefrom about 4 mm×4 mm to about 14 mm×14 mm. In some embodiments, theopening can be about 10 mm×7 mm.

In some embodiments, the method comprises forcing a cutting head taughtherein in a backward direction on a surface comprising the target tissueto remove the target tissue. The backward direction can include a forcevector that moves (i) at least substantially on a plane containing thecentral axis of the lumen of the cutting head, (ii) at leastsubstantially on the surface comprising the target tissue, and (iii)away from the perimeter tissue that is protected by the blade guard.

In some embodiments, the method comprises forcing a cutting head taughtherein in a transverse direction on a surface comprising the targettissue to remove the target tissue. The transverse direction, forexample, can include a force vector that moves (i) at an angle rangingfrom about 15° to about 165° from a plane containing the central axis ofthe lumen of the cutting head, (ii) at least substantially on thesurface comprising the target tissue, and (iii) in contact with theperimeter tissue that is protected by the blade guard.

The cutting heads taught herein are sharp and can be harmful to tissuesduring entry and exit of the cutting heads through the surgical opening.An obturator, guard cannula is provided in some embodiments to protect asubject during entry and exit of an elongated surgical cutting devicehaving a non-linearity.

FIG. 6 illustrates an obturator, guard cannula, according to someembodiments. The guard cannula 600 can comprise an entry hub 605 havingan inner perimeter 615, an outer perimeter 625, and an irrigation port635 that communicates between the inner perimeter 615 with the outerperimeter 625; and, a linear, elongated split-tube 650 having a proximalend 655, a distal end 665, and a lumen 675. In these embodiments, theproximal end 655 of the split-tube 650 can (i) circumscribe at least aportion of the inner perimeter 615 of the hub 605 and (ii) be inoperable communication with the irrigation port 635. In theseembodiments, the communication can be operable to receive an irrigationfluid 690 from the irrigation port 635, the transport of the irrigationfluid 690 to a target tissue (not shown) including, for example, amovement of the irrigation fluid 690 from the irrigation port 635 to thedistal end 665 of the split-tube 650 on a luminal surface 680 of thesplit-tube 650.

One of skill will appreciate that the “irrigation fluid” can be anyfluid desired by one of skill, including liquids and gases. In someembodiments, the irrigation fluid can be aqueous. In some embodiments,the irrigation fluid can be non-aqueous. And, in some embodiments, theirrigation fluid can be an emulsion. In some embodiments, the irrigationfluid can comprise a gas. Examples of aqueous irrigation fluids includewater, saline, or an aqueous surfactant containing liquid. Examples ofnon-aqueous fluids can include any oil-based liquid that may helpfacilitate tissue extraction during a surgical procedure. Examples ofgases can include carbon dioxide, nitrogen, air, and any inert or atleast substantially non-reactive gases. In some embodiments, theirrigation fluid can include a lubricant, such as glycerin, silicon oil,and the like. Irrigation fluids can be used as a carrier to help removean excised tissue, or to help inhibit the creation of a vacuum within asurgical site that can inhibit the removal of the excised tissue. Anexample of such as a vacuum is one that may be created during use of asuction within a closed cavity such as an intervertebral space within anannulus during a discectomy.

The distal end 665 of the split-tube 650 can also have any configurationdesired by one of skill. For example, the distal end 665 can be at leastsubstantially pointed and/or non-blunt. In some embodiments, the distalend 665 can be at least substantially blunt to avoid damage to an entrytissue upon contact of the distal end 665 with the entry tissue. Thesplit-tube 650 can also have a length ranging from about 10 cm to about60 cm and a width ranging from about 5 mm to about 16 mm. Moreover, thesplit in the split-tube 650 can compose a gap 667 having a width rangingfrom about 4 mm to about 14 mm, the split accommodating a non-linearityin the surgical device. In some embodiments, the cutting heads taughtherein can have a diameter that is smaller than that of the portion ofthe suction assembly that passes through the lumen of the guard cannula,such that the guard cannula holds the suction assembly 484 but allowsthe cutting head 400 to pass through the gap 667. As such, the gap 667can have a width that exceeds the diameter of the cutting head 400 butis less than the diameter of the rigid suction tube 488, and the lumenof the guard cannula 600 has a diameter that exceeds the diameter of therigid suction tube 488.

As described above, the systems taught herein can be used in a varietyof procedures for removal of a target tissue from a subject including,for example, removal of a meniscus or a discectomy. In some embodiments,the surgical cutting device used with the guard cannula can be adiscectomy device. And, in some embodiments, the entry tissue includesthe subject's epithelial tissue, muscle tissue, nerve tissue, connectivetissue, a blood vessel, bone, cartilage, or a combination thereof,leading to the nucleus pulposus. As such, the target tissue can includethe nucleus pulposus in some embodiments.

A surgical tissue removal kit having a surgical tissue removal systemand a guard cannula is provided, the kit using any combination of systemand cannula embodiments taught herein. In some embodiments, the kits canbe a discectomy kit. As such, in some embodiments, the entry tissueincludes the subject's epithelial tissue, muscle tissue, nerve tissue,connective tissue, a blood vessel, bone, cartilage, or a combinationthereof, leading to the nucleus pulposus. As such, the target tissue caninclude the nucleus pulposus in some embodiments.

FIG. 7 illustrates a surgical tissue removal kit, according to someembodiments. The kit 700 includes a cutting head 400, a suction assembly484, and an obturator, guard cannula 600. A flow of suction 444 from thesuction assembly 484 enters the cutting head 400 to remove a targettissue excised by the cutting head. Irrigation water 690 can enterirrigation valve 795 and/or the irrigation port 635, the irrigationwater 690 coming from the irrigation valve 795 is used when the suction444 is off, and the irrigation water 690 coming from the irrigation port635 can be used when the suction 444 is on, during which the suction 444draws the irrigation water 690 between the luminal surface of the guardcannula 600 and the suction assembly 484 into the surgical area (notshown). The guard cannula 600 protects the entry tissue (not shown)while the cutting head 400 and suction assembly 484 moves relative tothe entry tissue during a surgical procedure, the cutting head 400moving, for example, in a forward, backward, and/or transverse motion toexcise and remove the target tissue.

A method of using the kits to remove a target tissue is provided. Insome embodiments, the method comprises creating an opening in a subjectfor access to a target tissue; inserting the cutting head of the kitthrough the entry hub and the elongated split-tube of the guard cannulaof the kit; inserting the cutting head of the kit through the opening toaccess the target tissue in the subject while protecting the entrytissue with the blunt, distal end of the split-tube. Otherwise, methodsof using the tissue removal systems are the same or similar to thosetaught herein. One of skill will appreciate having such kits fordiscectomies, for example, in which the target tissue can be a nucleuspulposus, and the perimeter tissue can be an annulus fibrosis. One ofskill will also appreciate having a kit with a guard cannula that helpsprotect the subject's epithelial tissue, muscle tissue, nerve tissue,connective tissue, a blood vessel, bone, cartilage, or a combinationthereof, leading to the nucleus pulposus in such procedures.

FIGS. 8A-8C illustrate a system or kit that can irrigate concurrent withapplication of suction, and without the obturator, guard cannula inplace, according to some embodiments. FIG. 8A shows the completediscectomy system 800 including the cutting head 400, a means forapplying suction through the suction assembly 884, a control handle 886and a vacuum attachment 892, an irrigation tube 804, an irrigationcontrol 802, and an optional vacuum control 888.

In embodiments in which the cutting head angle is adjustable, the handle886 can have a knob (not shown) that turns to tension a pull cable toflex or straighten the cutting head relative to the rigid suction tube,or a slide that tensions the cable to flex or straighten the cuttinghead relative to the rigid suction tube. The cables to flex andstraighten can be on opposing sides of the shaft constrained to smallside lumens attached to the outer surface of the shaft to flex andstraighten out the cutting head.

FIG. 8B shows a cross-sectional view of the irrigation tube 804 relativeto the rigid suction tube 894. And, FIG. 8C shows a cross-sectional viewof the control handle 886 and internal piping.

One of skill will appreciate that the teachings and examples providedherein are directed to basic concepts that can extend beyond anyparticular embodiment, embodiments, figure, or figures. It should beappreciated that any examples are for purposes of illustration and arenot to be construed as otherwise limiting to the teachings.

EXAMPLE 1 Testing of Cutter Head Designs

A variety of cutter heads were tested in 3 cadaver laboratories on 28discs. The results were compared to determine the most efficient cutterhead design. A desirable cutter head design was one that would cut wellon all target tissues, including the nucleus pulposus, vertebralendplates, and inner annulus tissue. However, the cutter head shouldalso cut the target tissues in a desired manner while providing littleto no damage to the perimeter tissue, such tissue including theperimeter annulus fibrosis tissue that should be preserved as adesirable perimeter structure. In addition, the design should removetissue quickly under suction, such that the configuration of the headfacilitates the removal of the tissue under suction.

FIGS. 9A-9H show cutting head designs that were tested, according tosome embodiments. The design in FIG. 9A cut well but it was not as safeto the annulus as other designs. The design in FIG. 9B was safe to theannulus but it did not cut tough tissue well and showed too muchresistance. The design in FIG. 9C also did not penetrate tough tissuewell. The design in FIG. 9D did cut and decorticate well, but it cloggedon soft/elastic tissue. The design in FIG. 9E cut tough tissue well anddid not clog, and it also decorticates really well. It was also safe tothe annulus. The shape of the device however, did not reach the far sideof the nucleus pulposus. The design in FIG. 9F shows a bend that wasintroduced to the device to enable the cutting head of FIG. 9E to reachthe far side of the nucleus pulposus. The design in FIGS. 9G and 9H,however, showed the most efficient cutting head performance identifiedin the testing, removing 23 cc of material in 5 minutes.

EXAMPLE 2

This example further developed the designs of the cutting heads. Thedesign in FIGS. 8G and 8H were further investigated in 7 cadaver labsand 28 discs.

FIGS. 10A-10E illustrate the advancements in the cutting head, accordingto some embodiments. The design in FIG. 10A shows a cutting head havinga bevel on the outer surface of the cutting teeth, and the device cutpoorly and gouged soft bone. The design in FIG. 10B shows an ovalcutting head not having the bevel on the outer surface of the cuttingteeth, and the device had inconsistent cutting and gouged soft bone. Thedesign in FIG. 10C was shown for a comparison result using a ringcurette, and the device gouged soft bone. The design in FIG. 10D shows ashort cutting head with a single “talon” or pincer, and the deviceshowed the most appealing results to date with optimal cutting and nogouging. FIG. 10E is another proposed design, configured to perform withthe efficiency of the design of FIG. 10D, with the addition of a secondtalon that bends away from the lumen of the cutting head to serve as anadditional talon and blade guard.

The method used in this example was as follows:

-   1. Cutting a pilot hole of a 5-8 mm dimension in height and width;-   2. Pointing a 15° tip parallel to the vertebral endplates to cut and    expand the cavity medially and laterally;-   3. Gradually shaving down the endplates to hard tissue (cartilage or    bone); fluoroscopy was used to verify the depth of the tip; the tip    was used to shave along the curvature of the endplate; shaving was    stopped where bone was exposed (hard, rough, sticky, and red    aspirate identified as the endpoint); and, the handle of the device    is tilted (i) medially to decorticate lateral side, and (ii)    laterally to decorticate medial side;-   4. Sweeping the cutting head medially-lateraly against anterior    annulus to remove nucleus attached to the annulus and inner annulus    as needed;-   5. Pointing a 40° tip contralaterally and start shaving from    posterior annulus while tilting handle laterally to remove bulk    nucleus; and,-   6. Rotating the handle toward the endplate to further decorticate.

EXAMPLE 3

This example describes an alternate embodiment that was tested, referredto as the serpentine or bayonet configuration, in which the rigidsuction tube 488 can have at least two angles; an angle θ₁, and an angleθ₃.

FIGS. 11A-11C illustrate a bayonet-type communication between a cuttinghead and a suction assembly, according to some embodiments. It wasdiscovered that the distal end of the rigid suction tube 488 can beredirected in bayonet, or serpentine, fashion in order to facilitate animproved access of the cutting head to a target tissue during adiscectomy, for example. As shown in FIGS. 11A-11C, Angles θ₁ and θ₃ caneach be independently selected to range from about 0° to about 180°,with the limitation that (i) the net angle, θ₄, that is realized betweenthe central axis 415 of the lumen 410 of the cutting head 400 and thecentral axis 497 of the rigid suction tube 488 (extended as directedproximal to θ₁) ranges from 0° to 90°; and, (ii) the distance 498between the central axis 415 of the lumen 410 of the cutting head 400and the central axis 497 of the rigid suction tube 488 can range fromabout 2 mm to about 30 mm. And, in these embodiments, the central axisof the lumen can have a point of exit at the forward cutting blade, andthe point of exit is located at a transverse distance of about 3 mm toabout 25 mm

In some embodiments, the distance 498 between the from about 2.5 mm toabout 25 mm, from about 3 mm to about 25 mm, from about 4 mm to about 20mm, from about 5 mm to about 15 mm, from about 3 mm to about 25 mm, fromabout 7 mm to about 12 mm, from about 8 mm to about 10 mm, or any rangetherein in increments of 0.5 mm. As such, the distance 498 can be about2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about8 mm, about 9 mm, about 10 mm, about 12 mm, about 14 mm, about 16 mm,about 18 mm, about 20 mm, about 22 mm, about 24 mm, about 26 mm, about28 mm, about 30 mm, and any distance or range therein in increments of0.5 mm. In some embodiments, the distance between the vertex of θ₃ andthe distal end of the cutting head 400 can range from about 5 mm toabout 25 mm, from about 6 mm to about 20 mm, from about 7 mm to about 15mm, or any range therein in increments of 1 mm.

I claim:
 1. A tubular cutting head for removing a nucleus pulposus of asubject, the cutting head comprising an outer perimeter thatcircumscribes a lumen through the cutting head, the lumen having acentral axis and in an operable communication with an at leastsubstantially rigid tube; and, a cutting surface on a distal perimeterof the cutting head, the cutting surface having a forward cutting bladehaving a forward-directed cutting surface on a distal edge of the outerperimeter, the forward cutting blade configured for (i) cutting thenucleus pulposus tissue in a forward stroke of the cutting head and (ii)excising and directing entry of the excised nucleus pulposus tissue intothe lumen on the forward stroke; and, a blade guard positioned distal tothe forward cutting blade and configured to guard an annulus fibrosistissue from the forward cutting blade upon the forward stroke, the bladeguard configured with a first laterally-directed cutting surfaceconfigured for cutting the nucleus pulposus in a first transverse strokeof the cutting head in a first transverse direction, the firstlaterally-directed cutting surface adapted as a directional shift fromthe forward cutting direction of the forward cutting blade to the firsttransverse direction of the first laterally-directed cutting surface,the first laterally-directed cutting surface including an apex pointingaway from a plane that geometrically bisects the blade guard and thecentral axis; and, a second laterally-directed cutting surface opposingthe first laterally-directed cutting surface and configured for cuttingthe nucleus pulposus in a second transverse stroke of the cutting headin a second transverse direction, the second laterally-directed cuttingsurface adapted as a directional shift from the forward cuttingdirection of the forward cutting blade to the second transversedirection of the second laterally-directed cutting surface, the secondlaterally-directed cutting surface including an apex pointing away fromthe plane that geometrically bisects the blade guard and the centralaxis.
 2. The cutting head of claim 1, wherein the blade guard also has abackward cutting blade having a backward-directed cutting surface andconfigured with a barb to hook nucleus pulposus tissue for removal ofthe nucleus pulposus tissue in a backward stroke of the cutting head. 3.The cutting head of claim 1, wherein the first laterally-directedcutting surface, second laterally-directed cutting surface, or both alsohas a plurality of laterally-directed, serrated cutting surfaces.
 4. Thecutting head of claim 1, wherein the blade guard also has a backwardcutting blade having a backward-directed cutting surface and configuredwith a barb to hook nucleus pulposus tissue for removal of the nucleuspulposus tissue in a backward stroke of the cutting head; and, aplurality of sharp lateral cutting surfaces positioned on the bladeguard, each of the lateral cutting surfaces adapted as the directionalshift from a forward-directed cutting surface of the forward cuttingblade.
 5. The cutting head of claim 1, wherein the cutting head isformed from a single tube.
 6. A surgical, nucleus pulposus removalsystem, comprising: a tubular cutting head adapted for removing a targettissue of a subject, the cutting head having an outer perimeter thatcircumscribes a lumen through the cutting head, the lumen having acentral axis and in an operable communication with an at leastsubstantially rigid tube; a cutting surface on a distal perimeter of thetubular cutting head, the cutting surface having a forward cutting bladehaving a forward-directed cutting surface on a distal edge of the outerperimeter, the forward cutting blade configured for (i) cutting thenucleus pulposus tissue in a forward stroke of the cutting head and (ii)excising and directing entry of the excised nucleus pulposus tissue intothe lumen on the forward stroke; and, a blade guard positioned distal tothe forward cutting blade and configured to guard an annulus fibrosistissue from the forward cutting blade upon the forward stroke, the bladeguard configured with a first laterally-directed cutting surfaceconfigured for cutting the nucleus pulposus in a first transverse strokeof the cutting head in a first transverse direction, the firstlaterally-directed cutting surface adapted as a directional shift fromthe forward cutting direction of the forward cutting blade to the firsttransverse direction of the first laterally-directed cutting surface,the first laterally-directed cutting surface including an apex pointingaway from a plane that geometrically bisects the blade guard and thecentral axis; and, a second laterally-directed cutting surface opposingthe first laterally-directed cutting surface and configured for cuttingthe nucleus pulposus in a second transverse stroke of the cutting headin a second transverse direction, the second laterally-directed cuttingsurface adapted as a directional shift from the forward cuttingdirection of the forward cutting blade to the second transversedirection of the second laterally-directed cutting surface, the secondlaterally-directed cutting surface including an apex pointing away fromthe plane that geometrically bisects the blade guard and the centralaxis, wherein, the cutting head is configured for an operablecommunication between the lumen and a source of a suction, the outerperimeter adapted to circumscribe a flow of suction through the cuttinghead; and, a suction assembly in operable communication with the cuttinghead, the suction assembly comprising an at least substantially rigidsuction tube with a central axis and creating the flow of suction forremoving the excised nucleus pulposus tissue through the lumen and outof the subject.
 7. The system of claim 6, wherein the blade guard isalso the backward cutting blade, the guard having a double-edged bladetip that points back into the lumen at an angle, θ₂, of greater than 90°to trap tissue, cut tissue, or trap and cut tissue in the lumen in thebackwards stroke of the cutting head.
 8. The system of claim 6, whereinthe central axis of the lumen is at an angle, θ₁, ranging from about 5°to about 90° from the central axis of the rigid suction tube, and theforward cutting blade is located about 3 mm to about 25 mm from thevertex of the angle, θ₁.
 9. The system of claim 6, wherein the centralaxis of the lumen has a point of exit at the forward cutting blade, andthe point of exit is located at a transverse distance of about 3 mm toabout 25 mm that is orthogonal to the central axis of the rigid suctiontube.
 10. The system of claim 6, wherein the central axis of the lumenis at an angle, θ₁, ranging from 1° to 180° from the central axis of therigid suction tube, and the forward cutting blade is located 3 mm to 25mm from the vertex of the angle, θ₁; wherein, an additional angle, θ₃,is located 5 mm to 25 mm proximal to θ₁; angles θ₁ and θ₃ areindependently selected to range from about 0° to about 180°, with thelimitation that (i) the net angle, θ₄, between the central axis of thelumen of the cutting head and the central axis of the rigid suction tubelocated proximal to θ₃ ranges from 0° to 90°; and, (ii) the central axisof the lumen has a point of exit at the forward cutting blade, and thepoint of exit is located at a transverse distance of about 3 mm to about25 mm that is orthogonal to the central axis of the rigid suction tube.11. The system of claim 6, wherein the cutting head is formed from asingle tube.
 12. A surgical, tissue removal system for a discectomy,comprising: a tubular cutting head adapted for removing a nucleuspulposus tissue from a subject, the cutting head having an outerperimeter that circumscribes a lumen through the cutting head, the lumenhaving a central axis and in an operable communication with an at leastsubstantially rigid tube; a cutting surface on a distal perimeter of thetubular cutting head, the cutting surface having a forward cutting bladehaving a forward-directed cutting surface on a distal edge of the outerperimeter and configured for (i) cutting and excising the nucleuspulposus tissue in a forward stroke of the cutting head and (ii)directing entry of the cut and excised nucleus pulposus into the lumenon the forward stroke; and, a blade guard positioned distal to theforward cutting blade and configured to guard an annulus fibrosis tissuefrom the forward cutting blade upon the forward stroke, the blade guardincluding a transverse cutting blade having a plurality oflaterally-directed cutting surfaces including a first laterally-directedcutting surface and a second laterally-directed cutting surface thatopposes the first laterally-directed cutting surface, the firstlaterally-directed cutting surface and the second laterally-directedcutting surface each configured for cutting and excising the nucleuspulposus in a respective first and second transverse stroke of thecutting head, each of the laterally-directed cutting surfaces adapted asa directional shift from the forward-directed cutting surface of theforward cutting blade to a laterally-directed cutting surface, the firstlaterally-directed cutting surface and the second laterally-directedcutting surface each including an apex pointed away from a plane thatgeometrically bisects the blade guard and the central axis; and, asuction assembly in operable communication with the cutting head, thesuction assembly comprising an at least substantially rigid suction tubewith a central axis and creating the flow of suction for removing thenucleus pulposus tissue through the lumen and out of the subject. 13.The system of claim 12, wherein the central axis of the lumen of thecutting head is at an angle, θ₁, ranging from about 5° to about 90° fromthe central axis of the rigid suction tube, and the forward cuttingblade is located about 3 mm to about 25 mm from the vertex of the angle,θ₁.
 14. The system of claim 12, wherein the central axis of the lumen ofthe cutting head has a point of exit at the forward cutting blade, andthe point of exit is located at a transverse distance of about 3 mm toabout 25 mm that is orthogonal to the central axis of the rigid suctiontube.
 15. The system of claim 12, wherein the plurality of cuttingsurfaces include serrations.
 16. The system of claim 12, wherein thecentral axis of the lumen is at an angle, θ₁, ranging from 1° to 180°from the central axis of the rigid suction tube, and the forward cuttingblade is located 3 mm to 25 mm from the vertex of the angle, θ₁;wherein, an additional angle, θ₃, is located 5 mm to 25 mm proximal toθ₁; angles θ₁ and θ₃ are independently selected to range from about 0°to about 180°, with the limitation that (i) the net angle, θ₄, betweenthe central axis of the lumen of the cutting head and the central axisof the rigid suction tube located proximal to θ₃ ranges from 0° to 90°;and, (ii) the central axis of the lumen has a point of exit at theforward cutting blade, and the point of exit is located at a transversedistance of about 3 mm to about 25 mm that is orthogonal to the centralaxis of the rigid suction tube.
 17. The system of claim 12, furthercomprising a backward cutting blade having a backward-directed cuttingsurface and configured with a barb to hook nucleus pulposus tissue forremoval of the nucleus pulposus tissue in a backward stroke of thecutting head, wherein the backward cutting blade is configured as atalon, positioned on the distal edge of the outer perimeter for cuttingthe nucleus pulposus tissue in the backward stroke of the cutting head.18. The system of claim 12, wherein the blade guard is also a backwardcutting blade, the guard having a double-edged blade tip point back intothe lumen at an angle, θ₂, of greater than 90° to trap tissue, cuttissue, or trap and cut tissue in the lumen in the backwards stroke ofthe cutting head.
 19. The system of claim 12, wherein the cuttingsurface is serrated, and the transverse cutting blade has two opposinglaterally-directed cutting surfaces adapted as a directional shift fromthe forward-directed cutting surface of the forward cutting blade toeach of the two opposing respective sharp laterally-directed cuttingsurfaces for cutting the nucleus pulposus tissue in the transversestroke of the cutting head.
 20. The system of claim 12, wherein thecutting head is formed from a single tube.
 21. A method of removing anucleus pulposus tissue from a subject, the method comprising: creatingan opening in a subject for access to a nucleus pulposus tissue;inserting the cutting head of claim 1 through the opening to access thenucleus pulposus tissue in the subject; forcing the cutting head in aforward direction on a surface comprising the nucleus pulposus tissue toremove the nucleus pulposus tissue, the forward direction including aforce vector that moves (i) at least substantially on a plane containingthe central axis of the lumen of the cutting head to excise the nucleuspulposus tissue and direct entry of the excised nucleus pulposus tissueinto the lumen of the cutting head when forcing the cutting head in theforward direction, (ii) at least substantially on the surface comprisingthe nucleus pulposus tissue, and (iii) toward the annulus fibrosistissue that is protected by the blade guard; capturing the nucleuspulposus tissue in the lumen of the cutting head when forcing thecutting head in the forward direction; and, removing the excised nucleuspulposus tissue through the lumen and out of the subject through asuction assembly.
 22. The method of claim 21, the cutting head furthercomprising a backward cutting blade having a backward-directed cuttingsurface and configured with a barb to hook nucleus pulposus tissue forremoval of the nucleus pulposus tissue in a backward stroke of thecutting head, and the method further comprising forcing the cutting headin a backward direction on a surface comprising the nucleus pulposustissue to remove the nucleus pulposus tissue, the backward directionincluding a force vector that moves (i) at least substantially on aplane containing the central axis of the lumen of the cutting head, (ii)at least substantially on the surface comprising the nucleus pulposustissue, and (iii) away from the annulus fibrosis tissue that isprotected by the blade guard.
 23. The method of claim 21, furthercomprising forcing the cutting head in a transverse direction on asurface comprising the nucleus pulposus tissue to remove the nucleuspulposus tissue, the transverse direction including a force vector thatmoves (i) at an angle ranging from about 15° to about 150° from a planecontaining the central axis of the lumen of the cutting head, (ii) atleast substantially on the surface comprising the nucleus pulposustissue, and (iii) in contact with the annulus fibrosis tissue that isprotected by the blade guard.
 24. The method of claim 2, wherein thecutting head is formed from a single tube.